To Sherlock's delight, John didn't seem to care if the phone number was missing. John wasn't in the habit of ignoring the loss of such things when genuinely interested. Therefore, the doctor had no real interest in engaging in a romantic relationship with the woman, to begin with.
Life returned to normal for the pair. John went to work at the surgery and Sherlock solved easy cases from the comfort of their flat.
In the middle of the week before Valentine's Day Lestrade brought them a case. A woman had been murdered by a jealous lover; the method so ingenious it had taken until the night before Valentine's Day to discern it and for Sherlock and John to solve the case.
"Is it just me," asked John, panting beside Sherlock in the alley, watching the police haul away the dead woman's wife, "or do we really have more cases in February than in other months?"
"Sentiment, John." Sherlock pointed to the woman in the police car. "People will do remarkable things in the name of sentiment, including commit murder."
John hummed as he considered this. He knew Sherlock had taken the phone number given to him by the woman at the surgery out of his coat and stashed it somewhere. For all the man claimed that 'love was a defect' he obviously cared about things that would affect his and John's relationship in any way. This was, no doubt, why the detective had inserted himself 'accidentally' into so many of John's 'first dates'...
For his 'first date', with Sarah, he had bought three tickets to the Chinese Circus (which had incidentally been the disguise for a smuggling ring). For his date with Madeleine, he had invited himself to dinner, saying, as he seated himself at their table, ''She's using you to get revenge on the ex lover who she caught in bed with another man'. Thoroughly embarrassed, Madeline had grabbed her coat and run out of the restaurant, leaving her meal, untouched.
Looking thoroughly confused, as to why the woman had run off, Sherlock had given John a look that no-one else could pull off half as well as the Consulting Detective, a look that was equal parts triumph, and confusion, as if he was disappointed it had taken so little to scare the woman away. He had frowned slightly, "Not good?"
"Yeah," said John, "A bit 'not good'."
After Madeleine had come Yvette, and Sherlock had snuck into the cinema he knew they would most likely be attending. The detective had spent the whole film sitting behind the couple and complaining. When the film was over, Yvette had turned and snapped at John; "Couldn't you have done something about him?" she had pointed at Sherlock imperiously. "He sucked all the fun out of our evening."
John shrugged, "I had a good time."
The brunette huffed and walked out of the cinema, not once looking back at the pair.
"She's going to the nearest night club, to find a replacement for you," stated the detective.
Sherlock's deduction stung, but John smiled at the man wryly. "Sherlock…"
"That was a bloody awful film," he said, not meeting the doctor's knowing gaze.
John shook his head, chuckling. "Dinner?"
"Boring."
The crime solving pair stumbled up the stairwell to their flat, hoping they didn't wake Mrs Hudson on their way in. They collapsed together on the sofa, exhausted.
"John?" asked Sherlock, his face turned towards the other man.
"Mmm." John hummed, half asleep already.
"It's Valentine's Day." The clock read 1 a.m.
"Hmm?" John snuggled into Sherlock's shoulder, too tired to care what he was doing. Sherlock's arm wound around his body, pulling the doctor closer to the detective.
"Be my Valentine, John?"
John smiled into Sherlock's shoulder, "I've got a date, later."
"Be my Valentine anyway..."
"Okay. Angelo's for lunch?"
"Sounds marvelous, John." Sherlock pressed a kiss into the doctor's blond hair as the two drifted off to sleep, together, on the sofa.